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xo-expression2 xo-reader2: local symtab stack in PSM

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This commit is contained in:
Roland Conybeare 2026-01-30 10:26:35 -05:00
commit f5ccd99dd2
8 changed files with 127 additions and 21 deletions
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8
include/xo/reader2/DExpectFormalArglistSsm.hpp
View file

@ -71,14 +71,18 @@ namespace xo {
/** @defgroup scm-expectformalarglistssm-methods general methods **/
///@{
/** update state on incoming token @p tk, with overall parser state in @p psm **/
/** update state on incoming token @p tk, with overall parser state in @p p_psm **/
void on_leftparen_token(const Token & tk,
ParserStateMachine * p_psm);
/** update state on incoming token @p tk, with overall parser state in @p psm **/
/** update state on incoming token @p tk, with overall parser state in @p p_psm **/
void on_comma_token(const Token & tk,
ParserStateMachine * p_psm);
/** update state on incoming rightparen token @p tk, with overall parser state in @p p_psm **/
void on_rightparen_token(const Token & tk,
ParserStateMachine * p_psm);
///@}
/** @defgroup scm-expectformalarglistssm-ssm-facet syntaxstatemachine facet methods **/
///@{

4
include/xo/reader2/DLambdaSsm.hpp
View file

@ -144,8 +144,6 @@ namespace xo {
#ifdef NOT_YET
virtual const char * get_expect_str() const override;
virtual void on_formal_arglist(const std::vector<rp<Variable>> & argl,
parserstatemachine * p_psm) override;
virtual void on_leftbrace_token(const token_type & tk,
parserstatemachine * p_psm) override;
virtual void on_colon_token(const token_type & tk,
@ -173,10 +171,10 @@ namespace xo {
/** parsing state-machine state **/
lambdastatetype lmstate_ = lambdastatetype::lm_0;
#ifdef NOT_YET
/** lambda environment (for formal parameters) **/
DLocalSymtab * local_symtab_ = nullptr;
#ifdef NOT_YET
/** explicit return type (if supplied) **/
TypeDescr explicit_return_td_ = nullptr;

31
include/xo/reader2/ParserStateMachine.hpp
View file

@ -6,6 +6,8 @@
#pragma once
#include "ParserResult.hpp"
#include <xo/expression2/DGlobalSymtab.hpp>
#include <xo/expression2/DLocalSymtab.hpp>
#include <xo/expression2/DVariable.hpp>
#include <xo/expression2/StringTable.hpp>
#include <xo/tokenizer2/Token.hpp>
@ -47,6 +49,7 @@ namespace xo {
bool debug_flag() const noexcept { return debug_flag_; }
ParserStack * stack() const noexcept { return stack_; }
obj<AAllocator> expr_alloc() const noexcept { return expr_alloc_; }
DLocalSymtab * local_symtab() const noexcept { return local_symtab_; }
const ParserResult & result() const noexcept { return result_; }
/** true iff state machine is currently idle (at top-level) **/
@ -79,6 +82,15 @@ namespace xo {
**/
const DUniqueString * intern_string(std::string_view str);
/** push nested local symtab while parsing the body of a lambda expression;
* restore previous symtab at the end of lambda-expression definition.
* See @ref pop_local_symtab
**/
void push_local_symtab(DLocalSymtab * symtab);
/** pop nested symbol table from symbol-table stack **/
void pop_local_symtab();
/** add variable to current local environment (innermost lexical scope) **/
void upsert_var(DVariable * var);
@ -219,8 +231,10 @@ namespace xo {
* after encountering a parsing error.
**/
DArena::Checkpoint parser_alloc_ckp_;
/** parser stack. Memory from @ref parser_alloc_ **/
/** parser stack. Memory always from @ref parser_alloc_;
* elements that should survive parsing allocate from
* @ref expr_alloc_, see below.
**/
ParserStack * stack_ = nullptr;
/** Allocator for parsed expressions.
@ -239,6 +253,19 @@ namespace xo {
**/
obj<AAllocator> expr_alloc_;
/** symbol table with local bindings.
* non-null during parsing of lambda expressions.
* Always allocated from @p expr_alloc_.
* Push local symbol table here to remember local params
* during the body of a lambda expression.
**/
DLocalSymtab * local_symtab_ = nullptr;
/** global symbol table.
* Toplevel definitions go here.
**/
DGlobalSymtab * global_symtab_ = nullptr;
/** current output from parser **/
ParserResult result_;

25
src/reader2/DExpectFormalArglistSsm.cpp
View file

@ -126,6 +126,10 @@ namespace xo {
this->on_comma_token(tk, p_psm);
return;
case tokentype::tk_rightparen:
this->on_rightparen_token(tk, p_psm);
return;
// all the not-yet-handled cases
case tokentype::tk_lambda:
case tokentype::tk_def:
@ -139,7 +143,6 @@ namespace xo {
case tokentype::tk_bool:
case tokentype::tk_semicolon:
case tokentype::tk_invalid:
case tokentype::tk_rightparen:
case tokentype::tk_leftbracket:
case tokentype::tk_rightbracket:
case tokentype::tk_leftbrace:
@ -300,20 +303,22 @@ namespace xo {
this->get_expect_str());
}
#ifdef NOT_YET
void
expect_formal_arglist_xs::on_rightparen_token(const token_type & tk,
parserstatemachine * p_psm)
DExpectFormalArglistSsm::on_rightparen_token(const Token & tk,
ParserStateMachine * p_psm)
{
if (farglxs_type_ == formalarglstatetype::argl_1b) {
std::unique_ptr<exprstate> self = p_psm->pop_exprstate();
if (fastate_ == formalarglstatetype::argl_1b) {
DArray * args = argl_;
p_psm->top_exprstate().on_formal_arglist(this->argl_, p_psm);
} else {
exprstate::on_rightparen_token(tk, p_psm);
p_psm->pop_ssm();
p_psm->on_parsed_formal_arglist(args);
return;
}
p_psm->illegal_input_on_token("DExpectFormalArglistSsm::on_rightparen_token",
tk,
this->get_expect_str());
}
#endif
bool
DExpectFormalArglistSsm::pretty(const ppindentinfo & ppii) const

52
src/reader2/DLambdaSsm.cpp
View file

@ -9,6 +9,9 @@
#include "ssm/ISyntaxStateMachine_DExpectFormalArglistSsm.hpp"
#include "ParserStateMachine.hpp"
#include "syntaxstatetype.hpp"
#include <xo/expression2/DVariable.hpp>
#include <xo/expression2/detail/IExpression_DVariable.hpp>
//#include <xo/expression2/symtab/ISymbolTable_DLocalSymtab.hpp>
#include <xo/printable2/Printable.hpp>
#include <xo/facet/FacetRegistry.hpp>
#include <xo/arena/DArena.hpp>
@ -28,6 +31,7 @@
namespace xo {
using xo::print::APrintable;
using xo::mm::AAllocator;
using xo::mm::AGCObject;
using xo::facet::FacetRegistry;
using xo::reflect::typeseq;
@ -353,6 +357,54 @@ namespace xo {
DLambdaSsm::on_parsed_formal_arglist(DArray * arglist,
ParserStateMachine * p_psm)
{
if (lmstate_ == lambdastatetype::lm_1) {
this->lmstate_ = lambdastatetype::lm_2;
/// something with top env frame ?
/// TODO: arena-friendly non-gc-aware vector;
// use instead of DArray for arglist.
// something like DTypedArray<T>
/// create LocalSymtab from arglist
DLocalSymtab * symtab
= DLocalSymtab::_make_empty(p_psm->expr_alloc(),
p_psm->local_symtab(),
arglist->size());
assert(symtab);
for (DArray::size_type i = 0, n = arglist->size(); i < n; ++i) {
obj<AGCObject> param = arglist->at(i);
// sad! runtime poly conversion from obj<AGCObject>
// We on need this because of (suboptimally) using DArray to store arglist
obj<AExpression> param_expr
= FacetRegistry::instance().variant<AExpression,AGCObject>(param);
obj<AExpression,DVariable> param_var
= obj<AExpression,DVariable>::from(param_expr);
assert(param_expr.data());
assert(param_var.data());
Binding b = symtab->append_var(p_psm->expr_alloc(),
param_var.data()->name(),
param_var.data()->typeref());
assert(b.is_local());
this->local_symtab_ = symtab;
}
// stash env frame: records local variables while we handle lambda body
p_psm->push_local_symtab(symtab);
// control reenters via .on_colon_token() / .on_leftbrace_token()
return;
}
p_psm->illegal_parsed_formal_arglist("DLambdaSsm::on_parsed_formal_arglist",
arglist,
this->get_expect_str());

2
src/reader2/ParserStack.cpp
View file

@ -70,7 +70,7 @@ namespace xo {
std::size_t i_frame = 0;
while (frame) {
char buf[80];
char buf[32];
snprintf(buf, sizeof(buf), "[%lu]", i_frame);
auto ssm = (FacetRegistry::instance().variant

20
src/reader2/ParserStateMachine.cpp
View file

@ -88,6 +88,20 @@ namespace xo {
return stringtable_.intern(str);
}
void
ParserStateMachine::push_local_symtab(DLocalSymtab * symtab)
{
this->local_symtab_ = symtab;
}
void
ParserStateMachine::pop_local_symtab()
{
assert(local_symtab_);
this->local_symtab_ = local_symtab_->parent();
}
void
ParserStateMachine::upsert_var(DVariable * var)
{
@ -310,6 +324,12 @@ namespace xo {
xtag("expecting", expect_str),
xtag("ssm", ssm_name),
xtag("via", "ParserStateMachine::illegal_parsed_formal_arglist"));
assert(expr_alloc_);
auto errmsg = DString::from_str(expr_alloc_, errmsg_string);
this->capture_error(ssm_name, errmsg);
}
void

6
utest/SchematikaParser.test.cpp
View file

@ -327,11 +327,10 @@ namespace xo {
REQUIRE(result.is_incomplete());
}
#ifdef NOT_YET
{
auto & result = parser.on_token(Token::else_token());
auto & result = parser.on_token(Token::rightparen_token());
log && log("after else token:");
log && log("after rightparen token:");
log && log(xtag("parser", &parser));
log && log(xtag("result", result));
@ -340,6 +339,7 @@ namespace xo {
REQUIRE(result.is_incomplete());
}
#ifdef NOT_YET
{
auto & result = parser.on_token(Token::string_token("fooey"));